Ocean at the End of the Lane by Neil Gaimann

 It is a short book and without the complicated mythology of other Gaimann books, but it is very flowing and nostalgic and even a tearjerker at times. It starts when the protagonist returns to the lane where the house he grew up in used to be (torn down now to make space for a set of townhouses).  At the end of the lane there is a mystrerious, all-female, three-generational family, The  Hempstocks, living, on a farm with a large pond that the youngest Hempstock, Lettie, calls an Ocean. The middle-aged Hempstock is Ginnie and the eldest is called just The Old Mrs. Hempstock.

The narrator spends time with Lettie, who shows him another place, where other things live, after the tenant, an Opal Miner, kills himself in the family Mini Morris. One of the things from the other place comes to this world in the foot of the narrator when he is 7 years old and starts giving people money, while taking a human form, a pretty young woman called Ursula Monkton, who starts working for the narrator's family as a nanny and also has an affair with the father of the family. 

The narrator fights the monster, and Lettie helps by letting 'varmints' from another world in, who eat things like what Ursula Monkton is.  The varmints devour her, but they also want to eat the narrator who was a vessel/house for the thing to come from the other place.  Lettie and Ginnie try to protect the 7 year old, but the varmints are stronger.  Lettie throws herself on the top of his body while the varmints attack her and nearly kill her until the Old Mrs. Hempstock wakes from her sleep in her silvery form (she has seen the Big Bang, and will also see the next one) and orders the varmints to get out of this world, which they obey.

Lettie is interred in the pond on the Hempstock's farm, which turns into a veritable ocean, and Ginnie says that when her healing is finished, she will come back.  The narrator leaves the home town and has a full life far away in London, but still comes back every 10 years to check if Lettie has come back from the Ocean at the End of the Lane.